Knee osteoarthritis (OA) is a progressive disease that ultimately requires patients to receive a total knee arthroplasty (TKA) to replace the damaged structures within the knee with an artificial joint. Surgeons have many options when selecting an appropriate implant. Patients want a TKA that feels 'normal' and allows them to perform most activities without pain, stiffness, and other residual symptoms. However, 20% of patients remain unsatisfied with their surgery, regardless. This thesis aimed to examine the effect of implant selection during TKA on knee biomechanical function during various ADLs. Several gaps were identified within the review of literature: 1) patient-reported outcome measures cannot differentiate between medial ball and socket (MBS) and posterior stabilized (PS) implants, 2) most biomechanical studies were performed only in postoperative patients, and 3) studies that compared MBS and PS implants were primarily focused on level walking conditions, and overlooked tasks that placed more demand on the knee joint. Twenty-eight individuals with severe knee OA were randomized to receive either an MBS (n=14) or PS implant. They completed a biomechanical assessment within one month and one year after TKA and were compared to 14 controls of similar age, sex, and body mass index. They performed a variety of tasks which explored three main areas: 1) examine the alterations in gait variability among individuals with OA following a TKA procedure using either a PS or MBS implant; 2) enhance the understanding of the post-operative effects of TKA with either MBS and PS implants on knee biomechanics and muscle activities during level walking, as well as more demanding tasks such as descending a ramp or staircase; 3) simulate the dynamic knee joint loads in post-operative TKA patients with either PS or MBS implants during closed-chain, bilateral tasks such as sit-to-stand. Initially, a series of studies were performed to develop a new test called waveform-level variance inequality test (eqvartest), which had not been previously utilized in the literature. This test was used to identify discrepancies in gait variability pre and post-TKA in the gait cycle. Following TKA, patients showed decreased variability in knee moment and power at single-limb support. Neither the MBS nor PS implant provided the same level of variability as the control group, demonstrating reduced knee joint stability. The MBS group had a gait pattern closer to the control group during level walking, whereas the PS group walked with a stiffer knee. However, during more demanding ADLs, the differences were less apparent. During ramp descent, knee joint stability issues became prominent as MBS and PS groups adopted a 'cautious gait pattern,' widening their base of support and stiffening their knee to reduce loading. During stair descent, the MBS implant provided increased stability as it required less muscle activity than the PS, requiring greater hamstring muscle activation. During sit-to-stand, MBS and PS groups favoured their non-operated knee as they had reduced total vertical, medial, and lateral KCF on their operated knee compared to their non-operated side. This may be due to compensatory strategies developed through the progression of knee OA and may increase the risk of developing knee OA on the non-operated limb. The outcomes of this thesis can assist clinicians in selecting the most appropriate implant for their patients and guide them in designing rehabilitation programs that can enhance patient function following TKA.

The single leg squat (SLS) is a functional movement task that is commonly used by clinicians as both an evaluation and treatment tool. Across clinics and research labs, no standard SLS procedure exists and variations in non-stance leg position are typical. There is little information to guide clinicians in selecting the appropriate SLS variation for individual rehabilitation goals. Non-stance leg positioning during the SLS may influence lower extremity mechanics and muscle activity. It is unknown if, and to what extent, altering the non-stance leg position during the SLS affects how the SLS is performed. The purpose of this dissertation was to examine how healthy adults performed the SLS when asked to place their non-stance leg in 3 commonly used positions during the squat. We hypothesized that the position of the non-stance leg would have a nontrivial impact on how the SLS was performed and result in different stance leg mechanics and muscle activation levels. Sixteen females participated in Study 1, the same 16 females from Study 1 and 16 males participated in Study 2, and 17 adults (with some overlap of participants from Study 1 and Study 2) participated in Study 3. Kinematic data were recorded using a motion capture system, ground reaction force data were collected using the force plates in a split-belt instrumented treadmill, and muscle activity levels were quantified using a surface electromyography system. Results from all 3 studies supported our hypothesis. Study 1 indicated that different non-stance leg positions during the SLS affected the kinematics at the trunk, pelvis, and lower extremity and the lower extremity kinetics in females. Study 2 demonstrated that males also exhibited different kinematics and kinetics for the 3 SLS tasks with different non-stance leg positions. In addition, females and males performed the 3 SLS tasks differently, suggesting that they respond differently to altering the non-stance leg position. Study 3 indicated that hip muscle activation levels were affected by the non-stance leg position during the SLS. Our results suggest that clinicians and researchers should be mindful of the non-stance leg position during the SLS and be cautious of using SLS variations interchangeably. / 2021-06-30T00:00:00Z

The analysis of human movement is important for diagnosis of as wellas planning and evaluating treatments of disorders or injuries affectingmovement. Optical motion capture combined with force plates provideaccurate measurements, but are confined to laboratory settings limiting theirpotential usefulness in clinical applications. Efforts are made to movemeasurements out of the laboratory making them more accessible, cheaperand easier to use for healthcare providers. This work aimed to assess thefeasibility of doing motion analysis with a wearable system consisting ofIMUs and pressure insole sensors, while also developing a methodology thatcould be used for subsequent validation. Six subjects performed walking, sideskipping, squats, chair stands and a balance exercise, while data was collectedsimultaneously from the wearable system and optical motion capture withforce plates. For demonstration, data from one example subject was analysedand included in this work. The wearable system showed promising results formeasuring ground reaction force. Center of pressure errors were relativelyhigh, likely influenced by the choice of method for coordinate transformationbetween the systems. Joint angle errors varied from low to very high fordifferent trials. Ankle dorsiflexion angle showed low errors and pelvis tiltangle high errors for all motion types. There is a need to investigate thecause for these high errors before more measurements are conducted. Themethodology presented in this work can, with a few recommended changes,be used for future validation of the wearable motion analysis system.

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The exploration of underlying pathophysiology of speech disorders is hampered by the limitations in quantitative assessment of speech production. Current assessments are driven by measures that couple underlying processes of speech production with mechanisms that compensate for speech deficits. We propose a multifactorial approach to decouple these effects and examine underlying processes of speech motor control. In study 1 we conducted a sensorimotor characterization of speech motor control via altered sensory feedback techniques. We applied these measures to investigate effects of dopaminergic medication on laryngeal and articulatory motor control mechanisms in persons with Parkinson’s disease (PwPD). The study outcomes provide preliminary indication that dopaminergic medication may have a differential effect on laryngeal sensorimotor function in PwPD, with a normalization (reduction of atypically large responses) of auditory reflexive responses and an exacerbation (further reduction of atypically small responses) of auditory adaptive responses. The study outcomes also provide insight into the differential effects of dopaminergic medication on laryngeal and articulatory speech subsystems in PwPD. We hope the outcomes will eventually serve as a basis for designing better therapeutics focused on ameliorating voice and speech dysfunctions in PwPD. In study 2 we investigated laryngeal motor control in a population of individuals with and without hyperfunctional voice disorders (HVDs) using three different laryngeal kinematic measures extracted via high-speed video endoscopy techniques. We applied these measures to investigate differential effects of laryngeal tension, movement variability, and movement asymmetry present in individuals with HVDs. Results indicate that individuals with HVDs exhibit statistically significantly higher kinematic stiffness, spatiotemporal indices, and asymmetry indices across rate and effort conditions compared to controls, indicating higher laryngeal tension, production variability, and movement asymmetry. Laryngeal kinematics suggest differing underlying motor control strategies in individuals with HVD relative to controls, which may inform better understanding of the etiology of HVDs. The study outcomes also provide insight into the ability of laryngeal kinematics to differentiate underlying motor control strategies in individuals with various voice disorders with neurological and physiological pathophysiology that could provide crucial insight to guide future clinical intervention. In study 3, a novel neurocomputational model was developed, combining an established neurological framework of speech motor control, with a physics based vocal fold model. This numerical model decouples the neurological and physiological aspects of laryngeal motor control to provide important directions in expanding the understanding of the underlying pathophysiology of laryngeal motor control in PD and HVDs. The model has demonstrated capability to simulate different modes of laryngeal motor control, ranging from short-term (i.e., reflexive) and long-term (i.e., adaptive) auditory feedback paradigms, to generating prosodic contours in speech. LaDIVA can be used to expand the understanding of the physiology of human phonation to enable, for the first time, the investigation of causal effects of neural motor control in the fine structure of the vocal signal. / 2025-02-20T00:00:00Z

The influence of a 60-day strength training regime on the flat walking Tennessee Walking Horse (TWH) yearling performance was determined using behavioral, physiological, and biomechanical measurements. Four TWH yearlings participated in a 60-day strength training regime. Documentation was made on behavioral responses, and measurements were taken on respiratory rates and standing and flat walking kinematics. Means (SD) were determined for physiological and biomechanical variables, and paired t-tests (P=0.05) were performed. Morphometrics, kinematics, and temporal variables remained constant through training. The flat walk shared similar kinematics and temporal variables with the walk, except for the rhythm, bipedal support, head displacements, and hind fetlock joint motion. While respiratory rates were not significantly different in training response, the TWH yearling demonstrated more efficient respiration compared to the non-gaited trot. Training impact was limited to improved, desirable behavioral responses. Through survey responses by TWH trainers, additional training variables were indicated for future training protocols.

No description available.

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No description available.